The loneliest frog on Earth is dead, taking with him the hope of an entire species.

Toughie was a famed Rabbs’ fringe-limbed tree frog and the last known member of his species. He had mottled brown skin and a strange bird-like call. He was described as “handsome,” had his own Wikipedia page and won the hearts of race car drivers and movie directors.

The United Nations projected Toughie’s image onto its headquarters in New York City in 2014, as part of a campaign to raise awareness about the world’s sixth mass extinction ― a period scientists warn we’re about to enter.

Toughie was “a symbol of the extinction crisis,” National Geographic said Friday. The frog was found dead on Sept. 26 in his home at the Atlanta Botanical Garden, where he’d lived since 2005.

The extinction of any species is a tragedy, with rippling effects that impact not just fragile ecosystems but people’s communities as well. And Toughie’s death serves as a reminder of the many species that have been wiped out “before we even knew that they were there,” notes Mark Mandica, who worked with the amphibian and whose young son named the frog.

Scientists did not identify Toughie’s species, Ecnomiohyla rabborum ― a type of frog known for being excellent climbers and gliders ― until 2005. That was the year a group of researchers went to central Panama in a race to collect live animals before a deadly chytrid fungus engulfed the area.

“It was likened to just rescuing things from a burning house,” Mandica told National Geographic of the expedition.

It’s believed the Rabbs’ frog population did not survive the invasive fungus, which has been linked to climate change and poses a serious threat to amphibian populations worldwide. In Panama alone, the disease has led to the extinction of at least 30 frog species. Like the Rabbs’ frog, several of the lost species were newly discovered.

“[We] had a very short window to learn about the [Rabbs’ frog] in the wild before this disease struck the only known locality for the frog and the species vanished,” Mary Pat Matheson, president of Atlanta Botanical Garden told the Atlantic Journal-Constitution.

Toughie was rescued from Panama and brought to the Botanical Garden, where he lived alone in a climate-controlled facility known as the Frog Pod until his death.

The only other Rabbs’ frog known in captivity, also male, died at Zoo Atlanta in 2012.

We are at the beginning of the worst spate of species die-offs since the disappearance of the dinosaurs 65 million years ago, scientists say. At the current rate of extinction, at least one in six species could be wiped off the face of the Earth by 2100. That number could balloon to 3 in 4 in the centuries to come.

There have been stories of unlikely survival in the face of this crisis. A rare deer, believed to be locally extinct in Afghanistan, was later found to have survived decades of war and turmoil, for example. In the United Kingdom, an elm tree thought to have vanished there was discovered “hiding in plain sight” in the garden of the official Scottish residence of Britain’s Queen Elizabeth II.

But these stories of hope are in contrast to many tales of loss. Just this week, news broke that the rusty-patched bumble bee is on the path to extinction. The ploughshare tortoise, native to Madagascar, may only be around for another two years, scientists said.

Toughie’s death also reminds us of the many frog species that are under threat. Amphibians are one of the most endangered classes of animals on Earth (together with reptiles, amphibians are going extinct at an estimated 10,000 times the rate of all other organisms), according to a 2015 study.

Frogs were found to be particularly vulnerable to extinction. The study’s author, John Alroy of Macquarie University in Australia, concluded that more than 3 percent of all frog species have disappeared, largely since the 1970s.

“Hundreds more will be lost over the next century,” the study added.

As with the spread of chytrid fungus, scientists have pinpointed climate change as a critical factor in the frogs’ decline. Cold-blooded with extremely thin skins, amphibians are particularly sensitive to changes in temperature, humidity and air or water quality. Climate change has also been linked to a rise of deadly infectious diseases that have impacted frog populations worldwide.

“Global warming is wreaking havoc on amphibians,” warned ecologist J. Alan Pounds back in 2006, “and will cause staggering losses of biodiversity if we don’t do something fast.”---The Huffington Post